All letters in the top row are in their upper-case form; all letters in the bottom row are in their lower-case form.
The "z" belongs to the top because the top are all straight lines and the letters on the bottom has curves.
z was actually thrown out of the alphabet by the greeks. When it was put back in the alphabet they just put it last.
q,w,e,r,t,y,u,i,o,p
Lanthanide and Actinides solids and synthetics